71239561 has 2 divisors, whose sum is σ = 71239562. Its totient is φ = 71239560.

The previous prime is 71239547. The next prime is 71239621. The reversal of 71239561 is 16593217.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70879561 + 360000 = 8419^2 + 600^2 .

It is a cyclic number.

It is not a de Polignac number, because 71239561 - 2¹¹ = 71237513 is a prime.

It is not a weakly prime, because it can be changed into another prime (71239501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35619780 + 35619781.

It is an arithmetic number, because the mean of its divisors is an integer number (35619781).

Almost surely, 2^71239561 is an apocalyptic number.

It is an amenable number.

71239561 is a deficient number, since it is larger than the sum of its proper divisors (1).

71239561 is an equidigital number, since it uses as much as digits as its factorization.

71239561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11340, while the sum is 34.

The square root of 71239561 is about 8440.3531324228. The cubic root of 71239561 is about 414.5469697075.

The spelling of 71239561 in words is "seventy-one million, two hundred thirty-nine thousand, five hundred sixty-one".